Selected deprotection of protected functional polymers

ABSTRACT

A process for removing a protecting group from a polymer. Protected functional groups of a polymer may be deprotected by treating the polymer in the presence of an acid catalyst, including organic acids, mineral acids, heterogeneous acid systems, Lewis acids, and fluoride ion sources.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of application Ser. No. 08/679,291,filed Jul. 12, 1996, now U.S. Pat. No. 5,922,810, which is related tocommonly owned Provisional Application Serial No. 60/001,692, nowabandoned filed Jul. 31, 1995, and claims the benefit of its earlierfiling date under 35 U.S.C. 119(e).

FIELD OF THE INVENTION

The present invention relates to processes for removing protectinggroups from protected functionalized polymers.

BACKGROUND OF THE INVENTION

Mono- and di-functional polymers (i.e., telechelic polymers that containtwo functional groups per molecule at the termini of the polymer) havefound wide utility in many applications. For instance, telechelicpolymers have been employed as rocket fuel binders, in coatings andsealants and in adhesives. In addition, polymers that contain twohydroxyl groups per molecule can be co-polymerized with appropriatematerials to form polyesters, polycarbonates, and polyamides (see U.S.Pat. No. 4,994,526).

A variety of polymerization techniques, such as cationic and freeradical polymerizations, have been employed to prepare functionalpolymers. However, functionality can be best controlled with anionicpolymerization. Living anionic polymerization of styrene and dienemonomers were first described by Szwarc and his coworkers. See M.Szwarc, Nature 178, 1169 (1956) and M. Szwarc, et al., J.Am.Chem.Soc.78, 2656 (1956).

Various publications have discussed the use of protected functionalinitiators to provide telechelic polymers. An early approach to thepreparation of telechelic polymers is discussed in D. N. Schulz, et al.,J.Polym.Sci., Polym.Chem.Ed. 12, 153 (1974), which describes thereaction of a protected hydroxy initiator with butadiene. The resultantliving anion was quenched with ethylene oxide to afford mono-protecteddi-hydroxy polybutadiene. While excellent functionality (f=1.87-2.02)was achieved by this process, the protected initiator was insoluble inhydrocarbon solution. Therefore, the reaction was conducted in diethylether, and as a result, relatively high 1,2 microstructure (31-54%) wasobtained.

U.S. Pat. Nos. 5,331,058 and 5,362,699 to Shepherd, et al. discuss thepreparation of telechelic polymers in hydrocarbon solutions usingmonofunctional silyl ether initiators. These monofunctional silyl etherinitiators can be useful in producing dihydroxy (telechelic)polybutadienes having desirable characteristics, such as a molecularweight of typically 1,000 to 10,000, a 1,4 microstructure content oftypically 90%, and the like.

These and other anionic polymerization techniques, and in particularthose using protected functional initiators, can be useful for thepreparation of protected functional polymers. However, problems havebeen encountered in deprotecting or removing the protecting group fromfunctional polymer moieties. Typically, prior deprotecting processes canrequire the use of costly reagents, result in partial or essentially nocleavage of the protecting group, lack economic feasibility incommercial production (for example, require high temperatures, longreaction times, etc.), alter the polymer structure, and the like.

For example, U.S. Pat. Nos. 5,331,058 and 5,362,699 discuss the use oftetraalkylammonium fluorides in polar solvents as useful desilylationreagents. However, tetraalkylammonium fluoride reagents can be costlyand difficult to handle due to their toxicity (see discussion in U.S.Pat. No. 5,376,745). Further, it can be difficult to effectively removethe silyl protecting groups of these types of initiators usingtetraalkylammonium fluoride, and other, reagents. Other reagents, suchas tert-butyldimethylsilyl triflate, can alter the polymer structure.

SUMMARY OF THE INVENTION

The present invention provides processes for deprotecting functionalizedpolymers, including mono- and di-functional polymers and functionalizedmulti-branched or star polymers. In the invention, the protectedfunctionalized polymer is treated in the presence of an acid catalystunder conditions selected to remove at least one protecting group.Exemplary acid catalysts useful in the present invention include organicacids, mineral acids, heterogeneous acid systems, Lewis acids andfluoride ion sources.

The process of the invention is capable of being conducted at a varietyof temperatures and processing times, ranging from ambient to about 200°C., and from about one hour to about 24 hours, thus imparting flexibiltyto the deprotection process. Further, protected functionalized polymerscan be effectively deprotected in accordance with the invention usingrelatively mild conditions and with minimal or no structural changes inthe polymer. The process of the invention can also offer economies ofproduction, including reduced reaction times, temperatures, lowerreagent costs, and the like. Still further, deprotection conditions canalso be selected to provide selected deprotection of dissimilarprotecting groups, or to provide partial deprotection, as desired.

DETAILED DESCRIPTION OF THE INVENTION

The processes of the present invention are useful for deprotectingfunctionalized polymers, including mono- and di-functional polymers andfunctionalized multi-branched or star polymers. Polymers which can bedeprotected in accordance with the present invention can be representedby the following general formulas:

FG-(Q)_(d)—R_(n)—Z—J-[A(R¹R²R³)])  (I)

or

L[(Q)_(d)—R_(n)—Z—J-[A(R¹R²R³)]_(x)]_(m)  (II)

wherein FG is H or a protected or non-protected functional group; Q is asaturated or unsaturated hydrocarbyl group derived by incorporation of acompound selected from group consisting of conjugated dienehydrocarbons, alkenylsubstituted aromatic hydrocarbons, polar compounds,and mixtures thereof; d is an integer from 10 to 2000; R is a saturatedor unsaturated hydrocarbyl group derived by incorporation of a compoundselected from the group consisting of conjugated diene hydrocarbons,alkenylsubstituted aromatic hydrocarbons, and mixtures thereof; n is aninteger from 0 to 5; Z is a branched or straight chain hydrocarbon groupwhich contains 3-25 carbon atoms, optionally containing aryl orsubstituted aryl groups; J is oxygen, sulfur, or nitrogen;[A(R¹R²R³)]_(x) is a protecting group, in which A is an element selectedfrom Group IVa of the Periodic Table of Elements; R¹, R², and R³ areeach independently selected from the group consisting of hydrogen,alkyl, substituted alkyl groups containing lower alkyl, lower alkylthio,and lower dialkylamino groups, aryl or substituted aryl groupscontaining lower alkyl, lower alkylthio, and lower dialkylamino groups,and cycloalkyl and substituted cycloalkyl containing 5 to 12 carbonatoms; and x is dependent on the valence of J and varies from one when Jis oxygen or sulfur to two when J is nitrogen; L in Formula II is alinking or coupling agent, as described below; and m can be an integerfrom 3 to 50.

In the present invention, a polymer as represented by Formulas (I) or(II) above is treated with an acid catalyst which is suitable forremoving or cleaving the protecting group [A(R¹R²R³)]_(x). The processof the invention is particularly useful for the removal of alkyl etherprotecting groups wherein J is oxygen and A is carbon, although theinvention is not limited to removal of these groups.

The acid catalyst employed in accordance with the invention is generallyselected from the group consisting of organic acids (including withoutlimitation para-toluenesulfonic acid, trifluoroacetic acid, acetic acid,methanesulfonic acid, and the like), dilute mineral acids (includingwithout limitation hydrochloric acid, phosphoric acid, sulfuric acid,and the like, having a concentration between about 0.01 N and about 12N), heterogeneous acid systems (including without limitation acid ionexchange resins, such as Amberlyst® 15, a commercially availablepolystyrene-based resin with sulfonic acid groups, Dowex® 50, acommercially available polystyrene-based resin from Dow Chemical,Reillex® 425 HCl, a commercially available polyvinyl pyridine-basedresin from Reilly Tar and Chemical, acid clays, and the like), Lewisacids (including without limitation trimethylsilyl iodide, iron (III)chloride with acetic anhydride, boron trihalides, such as borontrifluoride, and the like) and suitable sources of fluoride ions, suchas tetraalkylammonium fluoride, such as tetrabutylammonium fluoride,potassium fluoride, sodium fluoride, cesium fluoride, lithium fluoride,lithium tetrafluoroborate, hydrogen fluoride, pyridine hydrogen fluoridecomplex, and the like.

The polymers of Formulas (I) and (II) can be treated under a variety ofconditions to deprotect the same. Reaction conditions can vary,depending, for example, on the type of acid catalyst employed, theprotecting group to be removed, the degree of deprotection required, thepresence of different protecting groups, and the like. Generally, thedeprotecting reaction is conducted at a temperature ranging from aboutambient (about 20° C.) to about 200° C., although higher or lowertemperatures can also be used. Reaction times can also vary, andtypically range from about 1 hour to 24 hours, although again higher orlower times can be used. The progress of the deprotection reactions canbe monitored by conventional analytical techniques, such as Thin LayerChromatography (TLC), Nuclear Magnetic Resonance (NMR), or InfraRed (IR)spectroscopy.

For example, organic acids, mineral acids, Lewis acids and fluoride ionsources can generally be used in polar or hydrocarbon solvents, ormixtures thereof, to deprotect the polymers of Formulas (I) and (II) attemperatures ranging from ambient to the reflux temperature of thereaction mixture. The organic acids, mineral acids, Lewis acids, andfluoride ion sources may also be used in excess amounts as solvents inthe deprotection process.

Protected functional polymers can be effectively deprotected usingheterogeneous acid systems without solvent, for example, by treating thepolymer with particles of an acidic ion exchange resin or otherheterogeneous acid systems and heat. Alternatively, the protectedfunctional polymer can be deprotected by heating the polymer with ahydrocarbon based two phase solution of the heterogeneous acid system upto the reflux temperature of the reaction mixture. The use of neatacidic ion exchange resins, and other heterogeneous acid systems, can beparticularly advantageous in commercial production because of therelative ease and efficiency of use (for example as a fluidized bed ofacid catalyst particles, through which the polymer to be deprotected iscontacted).

Hydrocarbon solvents useful in practicing this invention include, butare not limited to, inert liquid alkanes, cycloalkanes and aromaticsolvents such as alkanes and cycloalkanes containing five to ten carbonatoms, such as pentane, hexane, cyclohexane, methylcyclohexane, heptane,methylcycloheptane, octane, decane and the like, and aromatic solventscontaining six to ten carbon atoms such as toluene, ethylbenzene,p-xylene, m-xylene, o-xylene, n-propylbenzene, isopropylbenzene,n-butylbenzene, t-butylbenzene, and the like. Useful polar solventsinclude, but are not limited to, diethyl ether, dibutyl ether,tetrahydrofuran, 2-methyltetrahydrofuran, methyl tert-butyl ether,diazabicyclo[2.2.2]octane, triethylamine, tributylamine,N,N,N′,N′-tetramethylethylene diamine (TMEDA), 1,2-dimethoxyethane(glyme), alkali metal alkoxides and amino-substituted alkali metalalkoxides.

When FG is H, the resultant deprotected polymer is mono-functional,i.e., has a hydroxyl, thio or amino functionality when J is oxygen,sulfur, or nitrogen, respectively. FG can also be a functional group toprovide a di-functional polymer. The di-functional polymer may betelechelic, i.e., contain two functional groups which are the same permolecule at the termini of the polymer (FG and J are the same). Thepolymer can also be hetero-telechelic, having different functionalitiesat opposite ends of the polymer chain (FG and J are not the same).Further, FG can be protected or non-protected; when FG is protected, theFG protecting group can be the same or different from the[A(R¹R²R³)]_(x) protecting group.

The present invention also provides selective deprotection of functionalgroups of a polymer or mixtures of polymers. In this regard,deprotecting conditions can be selected to remove at least oneprotecting group without removing other dissimilar protecting groups, byproper selection of deprotecting reagents and conditions. For example,when polymer (I) includes a protected functional group FG as definedabove in addition to protecting group [A(R¹R²R³)]_(x), the polymer ofFormula (I) can be treated using the acid catalysts under conditions toselectively remove one or both of the protecting groups. Similarly, amixture of polymers according to Formulas (I) or (II) having differentprotecting groups [A(R¹R²R¹)]_(x), and/or protecting groups on thefunctional group FG which are the same or different from the protectinggroups [A(R¹R²R³)]_(x), can also be treated using the acid catalystsunder conditions to selectively remove one or more of the protectinggroups.

The following table details representative experimental conditionscapable of selectively removing protecting groups (more labile) whilemaintaining the integrity of other different protecting groups (morestable).

Labile Stable Conditions t-butyldimethylsilyl t-butyl tetrabutylammoniumfluoride t-butyldimethylsilyl t-butyl 1N HCL t-butyldimethylsilyldialkylamino tetrabutylammonium fluoride t-butyldimethylsilyldialkylamino 1N HCL t-butyl dialkylamino Amberlyst ® 15 resin t-amyldialkylamino Amberlyst ® 15 resin trimethylsilyl t-butyltetrabutylammonium fluoride trimethylsilyl t-butyl 1N HCl trimethylsilyldialkylamino tetrabutylammonium fluoride trimethylsilyl dialkylamino 1NHCl

Still further, the degree or amount of deprotection can also becontrolled in accordance with the present invention by suitableselection of deprotecting reaction conditions, acid catalyst, and thelike. In this regard, various reaction conditions and/or acid catalystscan be useful to partially deprotect the functional groups. For example,trifluoroacetic acid and trimethylsilyl iodide can be effective inpartially deprotecting tertiary alkyl ether protecting groups.

The polymers of Formulas (I) or (II) can be prepared by initiatingpolymerization of suitable compounds in a polar, hydrocarbon, or mixedhydrocarbon-polar solvent medium with a protected functionalorganolithium initiator to form an intermediate mono-protectedmono-functional living anion. For polar compounds, preferably, theinitiator is reacted with an appropriate diphenyl alkyl group, such as1,1-diphenylethylene, to provide a stabilized carbanion prior topolymerization.

The monomers may be polymerized singly, or in admixture with each otherto form tapered or random copolymers, or by charging the compounds tothe reaction mixture sequentially, to form block copolymers.

As noted above, the mono-protected mono-functional living anion can bequenched with a suitable proton donor, such as methanol, isopropanol,acetic acid, and the like, to provide a mono-functional polymer (whereinFG is H). Alternatively, polymerization can be followed byfunctionalization of the resultant living anion with a suitableelectrophile to provide a di-functional polymer. The di-functionalpolymer may be telechelic, i.e., contain two functional groups, whichare the same, per molecule at the termini of the polymer. The polymercan also be hetero-telechelic, having different functionalities atopposite ends of the polymer chain. This is represented schematically bythe formula A - - - B, wherein A and B are different functional groups.

Suitable conjugated diene hydrocarbons useful in the preparation of thefunctional polymers of Formulas (I) and (II) include, but are notlimited to, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene,1,3-pentadiene, myrcene, 2-methyl-3-ethyl-1,3-butadiene,2-methyl-3-ethyl-1,3-pentadiene, 1,3-hexadiene, 2-methyl-1,3-hexadiene,1,3-heptadiene, 3-methyl-1,3-heptadiene, 1,3-octadiene,3-butyl-1,3-octadiene, 3,4-dimethyl-1,3-hexadiene,3-n-propyl-1,3-pentadiene, 4,5-diethyl-1,3-octadiene,2,4-diethyl-1,3-butadiene, 2,3-di-n-propyl-1,3-butadiene, and2-methyl-3-isopropyl-1,3-butadiene.

Examples of polymerizable alkenylsubstituted aromatic hydrocarbonsinclude, but are not limited to, styrene, alpha-methylstyrene,vinyltoluene, 2-vinylpyridine, 4-vinylpyridine, 1-vinylnaphthalene,2-vinylnaphthalene, 1-alpha-methylvinylnaphthalene,2-alpha-methylvinylnaphthalene, 1,2-diphenyl-4-methyl-1-hexene andmixtures of these, as well as alkyl, cycloalkyl, aryl, alkylaryl andarylalkyl derivatives thereof in which the total number of carbon atomsin the combined hydrocarbon constituents is generally not greater than18. Examples of these latter compounds include 3-methylstyrene,3,5-diethylstyrene, 4-tert-butylstyrene, 2-ethyl-4-benzylstyrene,4-phenylstyrene, 4-p-tolylstyrene, 2,4-divinyltoluene and4,5-dimethyl-1-vinylnaphthalene. U.S. Pat. No. 3,377,404, incorporatedherein by reference in its entirety, discloses suitable additionalalkenylsubstituted aromatic hydrocarbons.

Suitable polar compounds include esters, amides, and nitriles of acrylicand methacrylic acid, and mixtures thereof. Exemplary polar monomersinclude, without limitation, methyl methacrylate, methyl acrylate,t-butyl methacrylate, t-butyl acrylate, ethyl methacrylate, andN,N-dimethylacrylamide.

Electrophiles that are useful in functionalizing the polymeric livinganion include, but are not limited to, alkylene oxides, such as ethyleneoxide, propylene oxide, styrene oxide, and oxetane; oxygen; sulfur;carbon dioxide; halogens such as chlorine, bromine and iodine;haloalkyltrialkoxysilanes, alkenylhalosilanes andomega-alkenylarylhalosilanes, such as chlorotrimethylsilane andstyrenyldimethyl chlorosilane; sulfonated compounds, such as 1,3-propanesultone; amides, including cyclic amides, such as caprolactam,N-benzylidene trimethylsilylamide, and dimethyl formamide; siliconacetals; 1,5-diazabicyclo[3.1.0]hexane; allyl halides, such as allylbromide and allyl chloride; methacryloyl chloride; amines, includingprimary, secondary, tertiary and cyclic amines, such as3-(dimethylamino)-propyl chloride andN-(benzylidene)trimethylsilylamine; epihalohydrins, such asepichlorohydrin, epibromohydrin, and epiiodohydrin, and other materialsas known in the art to be useful for terminating or end cappingpolymers. These and other useful functionalizing agents are described,for example, in U.S. Pat. Nos. 3,786,116 and 4,409,357, the entiredisclosure of each of which is incorporated herein by reference. Thepolymer is optionally hydrogenated before or after functionalizationand/or before or after deprotection.

Exemplary organolithium initiators useful in the present inventioninclude initiators selected from the group-consisting ofomega-(tert-alkoxy)-1-alkyllithiums, omega-(tert-alkoxy)-1-alkyllithiumschain extended with conjugated alkadienes, alkenylsubstituted aromatichydrocarbons, and mixtures thereof,omega-(tert-alkylthio)-1-alkyllithiums,omega-(tert-alkylthio)-1-alkyllithiums chain extended with conjugatedalkadienes, alkenylsubstituted aromatic hydrocarbons, and mixturesthereof, omega-(tert-butyldimethylsilyloxy)-1-alkyllithiums,omega-(tert-butyldimethylsilylthio)-1-alkyllithiums,omega-(dialkylamino)-1-alkyllithiums,omega-(dialkylamino)-1-alkyllithiums chain-extended with conjugatedalkadienes, alkenylsubstituted aromatic hydrocarbons, and mixturesthereof, and omega-(bis-tert-alkylsilylamino)-1-alkyllithiums.

Initiators useful in the preparation of polymers of Formulas (I) and(II) can also be represented by the following formula:

M—R_(n)—Z—J-[A(R¹R²R³)]_(x)  (III)

wherein M is an alkali metal; R is a saturated or unsaturatedhydrocarbyl group derived by incorporation of a compound selected fromthe group consisting of conjugated diene hydrocarbons,alkenylsubstituted aromatic hydrocarbons and mixtures thereof; n is aninteger from 0 to 5; Z is a branched or straight chain hydrocarbon groupwhich contains 3-25 carbon atoms, optionally containing aryl orsubstituted aryl groups; J is a hetero atom, e.g., oxygen, sulfur, ornitrogen; A is an element selected from Group IVa of the Periodic Tableof Elements; R¹, R², and R³ are each independently selected fromhydrogen, alkyl, substituted alkyl groups containing lower alkyl, loweralkylthio, and lower dialkylamino groups, aryl or substituted arylgroups containing lower alkyl, lower alkylthio, and lower dialkylaminogroups and cycloalkyl and substituted cycloalkyl containing 5 to 12carbon atoms; and x is dependent on the valence of J and varies from onewhen J is oxygen or sulfur to two when J is nitrogen.

These initiators can be prepared by reaction of protected organolithiumcompounds of the following formula:

M—Z—J-[A(R¹R²R³)]_(x)  (IV)

wherein each of M, Z, J, A, R¹, R², R³, and x are the same as definedabove with one or more conjugated alkadienes (such as butadiene orisoprene), alkenylsubstituted aromatic hydrocarbons (such as styrene oralpha-methylstyrene), and mixtures thereof, to form an extendedhydrocarbon chain between M and Z in Formula (IV), which extended chainis denoted as R_(n) in Formula (III).

The compounds of Formula (IV) can be prepared by reacting in an inertsolvent a selected tertiary amino-1-haloalkane,omega-hydroxy-protected-1-haloalkane, oromega-thio-protected-1-haloalkane, depending on whether J is to be N, Oor S, (the alkyl portions of the haloalkyl groups contain 3 to 25 carbonatoms) with an alkali metal, preferably lithium, at a temperaturebetween about 35° C. and about 130° C., preferably at the solvent refluxtemperature, to form a protected monofunctional alkali metal initiator(of Formula IV), which is then optionally reacted with a one or moreconjugated diene hydrocarbons, one or more alkenylsubstituted aromatichydrocarbons, or mixtures of one or more dienes with one or morealkenylsubstituted aromatic hydrocarbons, in a predominantly alkane,cycloalkane, or aromatic reaction solvent, which solvent contains 5 to10 carbon atoms, and mixtures of such solvents to produce amonofunctional initiator with an extended chain or tether between themetal atom (M) and element (J) in Formula (III) above and mixturesthereof with compounds of Formula (IV). R in Formula (III) is preferablyderived from conjugated 1,3-dienes. While A in the protecting group[A(R¹R²R³)] of the formulae above can be any of the elements in GroupIVa of the Periodic Table of the Elements, carbon and silicon currentlyappear the most useful, especially when polymerizing conjugated dienes.

Incorporation of R groups into the M—Z linkage to form the compounds ofFormula (III) above involves addition of compounds of the Formula

M—Z—J-[A(R¹R²R³)]_(x)

where the symbols have the meanings ascribed above, across the carbon tocarbon double bonds in compounds selected from the consisting of one ormore conjugated diene hydrocarbons, one or more alkenylsubstitutedaromatic hydrocarbons, or mixtures of one or more dienes with one ormore alkenylsubstituted aromatic hydrocarbons, to produce newcarbon-lithium bonds of an allylic or benzylic nature, much like thosefound in a propagating polyalkadiene or polyarylethylene polymer chainderived by anionic initiation of the polymerization of conjugated dienesor arylethylenes. These new carbon-lithium bonds are now activatedtoward polymerization and so are much more efficient in promotingpolymerization than the precursor M—Z (M=Li) bonds themselves.

Tertiary amino-1-haloalkanes useful in practicing this invention arecompounds of the following general structures:

X—Z—N[A(R¹R²R³)]₂

and

wherein X is halogen, preferably chlorine or bromine; Z is a branched orstraight chain hydrocarbon tether or connecting group which contains3-25 carbon atoms, which tether may also contain aryl or substitutedaryl groups; A is an element selected from Group IVa of the PeriodicTable of the Elements; R¹, R², and R³ are independently defined ashydrogen, alkyl, substituted alkyl groups containing lower alkyl, loweralkylthio, and lower dialkylamino groups, aryl or substituted arylgroups containing lower alkyl, lower alkylthio, and lower dialkylaminogroups, or cycloalkyl and substituted cycloalkyl groups containing 5 to12 carbon atoms; and m is an integer from 1 to 7, and their employmentas initiators in the anionic polymerization of olefin containingmonomers in an inert, hydrocarbon solvent optionally containing a Lewisbase. The process reacts selected tertiary amino-1-haloalkanes whosealkyl groups contain 3 to 25 carbon atoms, with lithium metal at atemperature between about 35° C. and about 130° C., preferably at thereflux temperature of an alkane, cycloalkane or aromatic reactionsolvent containing 5 to 10 carbon atoms and mixtures of such solvents.

Anionic polymerizations employing the tertiary amine initiators areconducted in an inert solvent, preferably a non-polar solvent,optionally containing an ethereal modifier, using an olefinic monomerwhich is an alkenylsubstituted aromatic hydrocarbon or a 1,3-diene at atemperature of about −30° C. to about 150° C. The polymerizationreaction proceeds from initiation to propagation and is finallyterminated with appropriate reagents so that the polymer ismono-functionally or di-functionally terminated. The polymers may have amolecular weight range of about 1000 to 10,000 but the molecular weightcan be higher. Typically 5 to 50 milli-moles of initiator is used permole of monomer.

Tertiary amino-1-haloalkanes useful in the practice of this inventioninclude, but are not limited to, 3-(N,N-dimethylamino)-1-propyl halide,3-(N,N-dimethylamino)-2-methyl-1-propyl halide,3-(N,N-dimethylamino)-2,2-dimethyl-1-propyl halide,4-(N,N-dimethylamino)-1-butyl halide, 5-(N,N-dimethylamino)-1-pentylhalide, 6-(N,N-dimethylamino)-1-hexyl halide,3-(N,N-diethylamino)-1-propyl halide,3-(N,N-diethylamino)-2-methyl-1-propyl halide,3-(N,N-diethylamino)-2,2-dimethyl-1-propyl halide,4-(N,N-diethylamino)-1-butyl halide, 5-(N,N-diethylamino)-1-pentylhalide, 6-(N,N-diethylamino)-1-hexyl halide,3-(N-ethyl-N-methylamino)-1-propyl halide,3-(N-ethyl-N-methylamino)-2-methyl-1-propyl halide,3-(N-ethyl-N-methylamino)-2,2-dimethyl-1-propyl halide,4-(N-ethyl-N-methylamino)-1-butyl halide,5-(N-ethyl-N-methylamino)-1-pentyl halide,6-(N-ethyl-N-methylamino)-1-hexyl halide, 3-(piperidino)-1-propylhalide, 3-(piperidino)-2-methyl-1-propyl halide,3-(piperidino)-2,2-dimethyl-1-propyl halide, 4-(piperidino)-1-butylhalide, 5-(piperidino)-1-pentyl halide, 6-(piperidino)-1-hexyl halide,3-(pyrrolidino)-1-propyl halide, 3-(pyrrolidino)-2-methyl-1-propylhalide, 3-(pyrrolidino)-2,2-dimethyl-1-propyl halide,4-(pyrrolidino)-1-butyl halide, 5-(pyrrolidino)-1-pentyl halide,6-(pyrrolidino)-1-hexyl halide, 3-(hexamethyleneimino)-1-propyl halide,3-(hexamethyleneimino)-2-methyl-1-propyl halide,3-(hexamethyleneimino)-2,2-dimethyl-1-propyl halide,4-(hexamethyleneimino)-1-butyl halide, 5-(hexamethyleneimino)-1-pentylhalide, 6-(hexamethyleneimino)-1-hexyl halide,3-(N-isopropyl-N-methyl)-1-propyl halide,2-(N-isopropyl-N-methyl)-2-methyl-1-propyl halide,3-(N-isopropyl-N-methyl)-2,2-dimethyl-1-propyl halide, and4-(N-isopropyl-N-methyl)-1-butyl halide. The halo- or halide group ispreferably selected from chlorine and bromine.omega-hydroxy-protected-1-haloalkanes useful in producing monofunctionalether initiators useful in practicing this invention have the followinggeneral structure:

X—Z—O-[C(R¹R²R³)]

wherein X is halogen, preferably chlorine or bromine; Z is a branched orstraight chain hydrocarbon group which contains 3-25 carbon atoms,optionally containing aryl or substituted aryl groups; and R¹, R², andR³ are independently defined as hydrogen, alkyl, substituted alkylgroups containing lower alkyl, lower alkylthio, and lower dialkylaminogroups, aryl or substituted aryl groups containing lower alkyl, loweralkylthio, and lower dialkylamino groups, or cycloalkyl and substitutedcycloalkyl groups containing 5 to 12 carbon atoms, and their employmentas initiators in the anionic polymerization of olefin containingmonomers in an inert, hydrocarbon solvent optionally containing a Lewisbase. The process reacts selected omega-hydroxy-protected-1-haloalkaneswhose alkyl groups contain 3 to 25 carbon atoms, with lithium metal at atemperature between about 35° C. and about 130° C., preferably at thereflux temperature of an alkane, cycloalkane or aromatic reactionsolvent containing 5 to 10 carbon atoms and mixtures of such solvents.

Anionic polymerizations employing the monofunctional ether initiatorsare conducted in an inert solvent, preferably a non-polar solvent,optionally containing an ethereal modifier, using an olefinic monomerwhich is an alkenylsubstituted aromatic hydrocarbon or a 1,3-diene at atemperature of about −30° C. to about 150° C. The polymerizationreaction proceeds from initiation to propagation and is finallyterminated with appropriate reagents so that the polymer ismono-functionally or di-functionally terminated. The polymers may have amolecular weight range of about 1000 to 10,000 but the molecular weightcan be higher. Typically 5 to 50 milli-moles of initiator is used permole of monomer.

The precursor omega-protected-1-haloalkanes (halides) can be preparedfrom the corresponding haloalcohol by standard literature methods. Forexample, 3-(1,1-dimethylethoxy)-1-chloropropane can be synthesized bythe reaction of 3-chloro-1-propanol with 2-methylpropene according tothe method of A. Alexakis, M. Gardette, and S. Colin, TetrahedronLetters, 29, 1988, 2951. The method of B. Figadere, X Franck and A.Cave, Tetrahedron Letters, 34, 1993, 5633, which involves the reactionof the appropriate alcohol with 2-methyl-2-butene catalyzed by borontrifluoride etherate, can be employed for the preparation of the t-amylethers. The alkoxy, alkylthio or dialkylamino substituted ethers, forexample 6-[3-(methylthio)-1-propyloxy]-1-chlorohexane, can besynthesized by reaction of the corresponding substituted alcohol, forinstance 3-methylthio-1-propanol, with analpha-bromo-omega-chloroalkane, for instance 1-bromo-6-hexane, accordingto the method of J. Almena, F. Foubelo and M. Yus, Tetrahedron, 51,1995, 11883. The compound 4-(methoxy)-1-chlorobutane, and the higheranalogs, can be synthesized by the ring opening reaction oftetrahydrofuran with thionyl chloride and methanol, according to theprocedure of T. Ferrari and P. Vogel, SYNLETT, 1991, 233. Thetriphenylmethyl protected compounds, for example3-(triphenylmethoxy)-1-chloropropane, can be prepared by the reaction ofthe haloalcohol with triphenylmethylchloride, according to the method ofS. K. Chaudhary and O. Hernandez, Tetrahedron Letters, 1979, 95.

Omega-hydroxy-protected-1-haloalkanes prepared in accordance with thisearlier process useful in practicing this invention include, but are notlimited to, 3-(1,1-dimethylethoxy)-1-propyl halide,3-(1,1-dimethylethoxy)-2-methyl-1-propyl halide,3-(1,1-dimethylethoxy)-2,2-dimethyl-1-propyl halide,4-(1,1-dimethylethoxy)-1-butyl halide, 5-(1,1-dimethylethoxy)-1-pentylhalide, 6-(1,1-dimethylethoxy)-1-hexyl halide,8-(1,1-dimethylethoxy)-1-octyl halide, 3-(1,1-dimethylpropoxy)-1-propylhalide, 3-(1,1-dimethylpropoxy)-2-methyl-1-propyl halide,3-(1,1-dimethylpropoxy)-2,2-dimethyl-1-propyl halide,4-(1,1-dimethylpropoxy)-1-butyl halide, 5-(1,1-dimethylpropoxy)-1-pentylhalide, 6-(1,1-dimethylpropoxy)-1-hexyl halide,8-(1,1-dimethylpropoxy)-1-octyl halide, 4-(methoxy)-1-butyl halide,4-(ethoxy)-1-butyl halide, 4-(propyloxy)-1-butyl halide,4-(1-methylethoxy)-1-butyl halide,3-(triphenylmethoxy)-2,2-dimethyl-1-propyl halide,4-(triphenylmethoxy)-1-butyl halide,3-[3-(dimethylamino)-1-propyloxy]-1-propyl halide,3-[2-(dimethylamino)-1-ethoxy]-1-propyl halide,3-[2-(diethylamino)-1-ethoxy]-1-propyl halide,3-[2-(diisopropyl)amino)-1-ethoxy]-1-propyl halide,3-[2-(1-piperidino)-1-ethoxy]-1-propyl halide,3-[2-(1-pyrrolidino)-1-ethoxy]-1-propyl halide,4-[3-(dimethylamino)-1-propyloxy]-1-butyl halide,6-[2-(1-piperidino)-1-ethoxy]-1-hexyl halide,3-[2-(methoxy)-1-ethoxy]-1-propyl halide,3-[2-(ethoxy)-1-ethoxy]-1-propyl halide,4-[2-(methoxy)-1-ethoxy]-1-butyl halide,5-[2-(ethoxy)-1-ethoxy]-1-pentyl halide,3-[3-(methylthio)-1-propyloxy]-1-propyl halide,3-[4-(methylthio)-1-butyloxy]-1-propyl halide,3-(methylthiomethoxy)-1-propyl halide,6-[3-(methylthio)-1-propyloxy]-1-hexyl halide,3-[4-(methoxy)-benzyloxy]-1-propyl halide,3-[4-(1,1-dimethylethoxy)-benzyloxy]-1-propyl halide,3-[2,4-(dimethoxy)-benzyloxy]-1-propyl halide,8-[4-(methoxy)-benzyloxy]-1-octyl halide,4-[4-(methylthio)-benzyloxy]-1-butyl halide,3-[4-(dimethylamino)-benzyloxy]-1-propyl halide,6-[4-(dimethylamino)-benzyloxy]-1-hexyl halide,5-(triphenylmethoxy)-1-pentyl halide, 6-(triphenylmethoxy)-1-hexylhalide, and 8-(triphenylmethoxy)-1-octyl halide. The halo- or halidegroup is preferably selected from chlorine and bromine.

U.S. Pat. No. 5,362,699 discloses a process for the preparation ofhydrocarbon solutions of monofunctional ether initiators derived fromomega-hydroxy-silyl-protected-1-haloalkanes of the following generalstructure:

X—Z—O-[Si(R¹R²R³)]

wherein X is halogen, preferably chlorine or bromine; Z is a branched orstraight chain hydrocarbon group which contains 3-25 carbon atoms,optionally containing aryl or substituted aryl groups; and R¹, R², andR³ are independently defined as saturated and unsaturated aliphatic andaromatic radicals, and their employment as initiators in the anionicpolymerization of olefin containing monomers in an inert, hydrocarbonsolvent optionally containing a Lewis base. The process reacts selectedomega-hydroxy-protected-1-haloalkanes whose alkyl groups contain 3 to 25carbon atoms, with lithium metal at a temperature between about 25° C.and about 40° C., in an alkane or cycloalkane reaction solventcontaining 5 to 10 carbon atoms and mixtures of such solvents.

Anionic polymerizations employing the monofunctional siloxy etherinitiators are conducted in an inert solvent, preferably a non-polarsolvent, optionally containing an ethereal modifier, using an olefinicmonomer which is an alkenylsubstituted aromatic hydrocarbon or a1,3-diene at a temperature of about −30° C. to about 150° C. Thepolymerization reaction proceeds from initiation to propagation and isfinally terminated with appropriate reagents so that the polymer ismono-functionally or di-functionally terminated. The polymers may have amolecular weight range of about 1000 to 10,000 but the molecular weightcan be higher. Typically 5 to 50 milli-moles of initiator is used permole of monomer.

Omega-silyl-protected-1-haloalkanes prepared in accordance with thisearlier process useful in practicing this invention include, but are notlimited to, 3-(t-butyldimethylsilyloxy)-1-propyl halide,3-(t-butyldimethyl-silyloxy)-2-methyl-1-propyl halide,3-(t-butyldimethylsilyloxy)-2,2-dimethyl-1-propyl halide,4-(t-butyldimethylsilyloxy)-1-butyl halide,5-(t-butyldimethyl-silyloxy)-1-pentyl halide,6-(t-butyldimethylsilyloxy)-1-hexyl halide,8-(t-butyldimethylsilyloxy)-1-octyl halide,3-(t-butyldiphenylylsilyloxy)-1-propyl halide,3-(t-butyldiphenylylsilyloxy)-2-methyl-1-propyl halide,3-(t-butyldiphenylylsilyloxy)-2,2-dimethyl-1-propyl halide,4-(t-butyldiphenylylsilyloxy)-1-butyl halide,6-(t-butyldiphenylsilyloxy)-1-hexyl halide and3-(trimethylsilyloxy)-2,2-dimethyl-1-propyl halide. The halo- or halidegroup is preferably selected from chlorine and bromine.

Monofunctional thioether initiators useful in the practice of thisinvention are derived from omega-thio-protected-1-haloalkanes of thefollowing general structure:

X—Z—S-[A(R¹R²R³)]

wherein X is halogen, preferably chlorine or bromine; Z is a branched orstraight chain hydrocarbon group which contains 3-25 carbon atoms,optionally containing aryl or substituted aryl groups; [A(R¹R²R³)] is aprotecting group in which A is an element selected from Group IVa of thePeriodic Table of the Elements, and R¹, R², and R³ are independentlydefined as hydrogen, alkyl, substituted alkyl groups containing loweralkyl, lower alkylthio, and lower dialkylamino groups, aryl orsubstituted aryl groups containing lower alkyl, lower alkylthio, andlower dialkylamino groups, or cycloalkyl and substituted cycloalkylgroups containing 5 to 12 carbon atoms, and their employment asinitiators in the anionic polymerization of olefin containing monomersin an inert, hydrocarbon solvent optionally containing a Lewis base. Theprocess reacts selected omega-thioprotected-1-haloalkyls whose alkylgroups contain 3 to 25 carbon atoms, with lithium metal at a temperaturebetween about 35° C. and about 130° C., preferably at the refluxtemperature of an alkane, cycloalkane or aromatic reaction solventcontaining 5 to 10 carbon atoms and mixtures of such solvents.

Anionic polymerizations employing the monofunctional thioetherinitiators are conducted in an inert solvent, preferably a non-polarsolvent, optionally containing an ethereal modifier, using an olefinicmonomer which is an alkenylsubstituted aromatic hydrocarbon or a1,3-diene at a temperature of about −30° C. to about 150° C. Thepolymerization reaction proceeds from initiation to propagation and isfinally terminated with appropriate reagents so that the polymer ismono-functionally or di-functionally terminated. The polymers may have amolecular weight range of about 1000 to 10,000 but the molecular weightcan be higher. Typically 5 to 50 milli-moles of initiator is used permole of monomer.

The initiator precursor, omega-thio-protected-1-haloalkanes (halides),can be prepared from the corresponding halothiol by standard literaturemethods. For example, 3-(1,1-dimethylethylthio)-1-propylchloride can besynthesized by the reaction of 3-chloro-1-propanthiol with2-methylpropene according to the method of A. Alexakis, M. Gardette, andS. Colin, Tetrahedron Letters, 29, 1988, 2951. Alternatively, reactionof 1,1-dimethylethylthiol with 1-bromo-3-chloropropane and a baseaffords 3-(1,1-dimethylethylthio)-1-propylchloride. The method of B.Figadere, X. Franck and A. Cave, Tetrahedron Letters, 34, 1993, 5893,which involves the reaction of the appropriate thiol with2-methyl-2-butene catalyzed by boron trifluoride etherate, can beemployed for the preparation of the t-amyl ethers. Additionally,5-(cyclohexylthio)-1-pentylhalide and the like, can be prepared by themethod of J. Almena, F. Foubelo, and M. Yus, Tetrahedron, 51, 1995,11883. This synthesis involves the reaction of the appropriate thiolwith an alkyllithium, then reaction of the lithium salt with thecorresponding alpha, omega dihalide. 3-(Methylthio)-1-propylchloride canbe prepared by chlorination of the corresponding alcohol with thionylchloride, as taught by D. F. Taber and Y. Wang, J. Org, Chem., 58, 1993,6470. Methoxymethylthio compounds, such as6-(methoxymethylthio)-1-hexylchloride, can be prepared by the reactionof the omega-chloro-thiol with bromochloromethane, methanol, andpotassium hydroxide, by the method of F. D. Toste and I. W. J. Still,Synlett, 1995, 159. T-Butyldimethylsilyl protected compounds, forexample 4-(t-butyldimethylsilylthio)-1-butylhalide, can be prepared fromt-butyldimethylchlorosilane, and the corresponding thiol, according tothe method described in U.S. Pat. No. 5,493,044.

Omega-thio-protected 1-haloalkanes prepared in accordance with thisearlier process useful in practicing this invention include, but are notlimited to, 3-(methylthio)-1-propylhalide,3-(methylthio)-2-methyl-1-propylhalide,3-(methylthio)-2,2-dimethyl-1-propylhalide,4-(methylthio)-1-butylhalide, 5-(methylthio)-1-pentylhalide,6-(methylthio)-1-hexylhalide, 8-(methylthio)-1-octylhalide,3-(methoxymethylthio)-1-propylhalide,3-(methoxymethylthio)-2-methyl-1-propylhalide,3-(methoxymethylthio)-2,2-dimethyl-1-propylhalide,4-(methoxymethylthio)-1-butylhalide,5-(methoxymethylthio)-1-pentylhalide,6-(methoxymethylthio)-1-hexylhalide,8-(methoxymethylthio)-1-octylhalide,3-(1,1-dimethylethylthio)-1-propylhalide,3-(1,1-dimethylethylthio)-2-methyl-1-propylhalide,3-(1,1-dimethylethylthio)-2,2-dimethyl-1-propylhalide,4-(1,1-dimethylethylthio)-1-butylhalide,5-(1,1-dimethylethylthio)-1-pentylhalide,6-(1,1-dimethylethylthio)-1-hexylhalide,8-(1,1-dimethylethylthio)-1-octylhalide,3-(1,1-dimethylpropylthio)-1-propylhalide,3-(1,1-dimethylpropylthio)-2-methyl-1-propylhalide,3-(1,1-dimethylpropylthio)-2,2-dimethyl-1-propylhalide,4-(1,1-dimethylpropylthio)-1-butylhalide,5-(1,1-dimethylpropylthio)-1-pentylhalide,6-(1,1-dimethylpropylthio)-1-hexylhalide,8-(1,1-dimethylpropylthio)-1-octylhalide,3-(cyclopentylthio)-1-propylhalide,3-(cyclopentylthio)-2-methyl-1-propylhalide,3-(cyclopentylthio)-2,2-dimethyl-1-propylhalide,4-(cyclopentylthio)-1-butylhalide, 5-(cyclopentylthio)-1-pentylhalide,6-(cyclopentylthio)-1-hexylhalide, 8-(cyclopentylthio)-1-octylhalide,3-30 (cyclohexylthio)-1-propylhalide,3-(cyclohexylthio)-2-methyl-1-propylhalide,3-(cyclohexylthio)-2,2-dimethyl-1-propylhalide,4-(cyclohexylthio)-1-butylhalide, 5-(cyclohexylthio)-1-pentylhalide,6-(cyclohexylthio)-1-hexylhalide, 8-(cyclohexylthio)-1-octylhalide,3-(t-butyldimethylsilylthio)-1-propylhalide,3-(t-butyldimethylsilylthio)-2-methyl-1-propylhalide,3-(t-butyldimethylsilylthio)-2,2-dimethyl-1-propylhalide,3-(t-butyldimethylsilylthio)-2-methyl-1-propylhalide,4-(t-butyldimethylsilylthio)-1-butylhalide,6-(t-butyldimethylsilylthio)-1-hexylhalide and3-(trimethylsilylthio)-2,2-dimethyl-1-propylhalide. The halo- or halidegroup is preferably selected from chlorine and bromine.

Examples of functionalized organolithium initiators (III) include, butare not limited to, tert-alkoxy-alkyllithiums such as3-(1,1-dimethylethoxy)-1-propyllithium and its more hydrocarbon-solubleisoprene chain-extended oligomeric analog (n=2),3-(tert-butyldimethylsilyloxy)-1-propyllithium (n=0),tert-alkylthio-alkyllithiums such as3-(1,1-dimethylethylthio)-1-propyllithium and its morehydrocarbon-soluble isoprene chain-extended oligomeric analog (n=2),3-(dimethylamino)-1-propyllithium and its more hydrocarbon-solubleisoprene chain-extended oligomeric analog (n=2) and3-(di-tert-butyldimethylsilylamino)-1-propyllithium, and mixturesthereof. Further examples of protected functionalized initiators thatmay be employed in this invention include, but are not limited to,3-(1,1-dimethylethoxy)-1-propyllithium,3-(1,1-dimethylethoxy)-2-methyl-1-propyllithium,3-(1,1-dimethylethoxy)-2,2-dimethyl-1-propyllithium,4-(1,1-dimethylethoxy)-1-butyllithium,5-(1,1-dimethylethoxy)-1-pentyllithium,6-(1,1-dimethylethoxy)-1-hexyllithium,8-(1,1-dimethylethoxy)-1-octyllithium,3-(1,1-dimethylpropoxy)-1-propyllithium,3-(1,1-dimethylpropoxy)-2-methyl-1-propyllithium,3-(1,1-dimethylpropoxy)-2,2-dimethyl-1-propyllithium,4-(1,1-dimethylpropoxy)-1-butyllithium,5-(1,1-dimethylpropoxy)-1-pentyllithium,6-(1,1-dimethylpropoxy)-1-hexyllithium,8-(1,1-dimethylpropoxy)-1-octyllithium,3-(t-butyldimethylsilyloxy)-1-propyllithium,3-(t-butyldimethylsilyloxy)-2-methyl-1-propyllithium,3-(t-butyldimethylsilyloxy)-2,2-dimethyl-1-propyllithium,4-(t-butyldimethylsilyloxy)-1-butyllithium,5-(t-butyldimethylsilyloxy)-1-pentyllithium,6-(t-butyldimethylsilyloxy)-1-hexyllithium,8-(t-butyldimethylsilyloxy)-1-octyllithium and3-(trimethylsilyloxy)-2,2-dimethyl-1-propyllithium,3-(dimethylamino)-1-propyllithium,3-(dimethylamino)-2-methyl-1-propyllithium,3-(dimethylamino)-2,2-dimethyl-1-propyllithium,4-(dimethylamino)-1-butyllithium, 5-(dimethylamino)-1-pentyllithium,6-(dimethylamino)-1-hexyllithium, 8-(dimethylamino)-1-propyllithium,4-(ethoxy)-1-butyllithium, 4-(propyloxy)-1-butyllithium,4-(1-methylethoxy)-1-butyllithium,3-(triphenylmethoxy)-2,2-dimethyl-1-propyllithium,4-(triphenylmethoxy)-1-butyllithium,3-[3-(dimethylamino)-1-propyloxy]-1-propyllithium,3-[2-(dimethylamino)-1-ethoxy]-1-propyllithium,3-[2-(diethylamino)-1-ethoxy]-1-propyllithium,3-[2-(diisopropyl)amino)-1-ethoxy]-1-propyllithium,3-[2-(1-piperidino)-1-ethoxy]-1-propyllithium,3-[2-(1-pyrrolidino)-1-ethoxyl-1-propyllithium,4-[3-(dimethylamino)-1-propyloxy]-1-butyllithium,6-(2-(1-piperidino)-1-ethoxy]-1-hexyllithium,3-[2-(methoxy)-1-ethoxy]-1-propyllithium,3-(2-(ethoxy)-1-ethoxyl-1-propyllithium,4-[2-(methoxy)-1-ethoxy]-1-butyllithium,5-[2-(ethoxy)-1-ethoxy]-1-pentyllithium,3-[3-(methylthio)-1-propyloxy]-1-propyllithium,3-[4-(methylthio)-1-butyloxy]-1-propyllithium,3-(methylthiomethoxy)-1-propyllithium,6-[3-(methylthio)-1-propyloxy]-1-hexyllithium,3-[4-(methoxy)-benzyloxy]-1-propyllithium,3-[4-(1,1-dimethylethoxy)-benzyloxy]-1-propyllithium,3-[2,4-(dimethoxy)-benzyloxy]-1-propyllithium,8-[4-(methoxy)-benzyloxy]-1-octyllithium,4-[4-(methylthio)-benzyloxy]-1-butyllithium,3-[4-(dimethylamino)-benzyloxy]-1-propyllithium,6-[4-(dimethylamino)-benzyloxy]-1-hexyllithium,5-(triphenylmethoxy)-1-pentyllithium,6-(triphenylmethoxy)-1-hexyllithium, and8-(triphenylmethoxy)-1-octyllithium,3-(hexamethyleneimino)-1-propyllithium,4-(hexamethyleneimino)-1-butyllithium,5-(hexamethyleneimino)-1-pentyllithium,6-(hexamethyleneimino)-1-hexyllithium,8-(hexamethyleneimino)-1-octyllithium,3-(t-butyldimethylsilylthio)-1-propyllithium,3-(t-butyldimethylsilylthio)-2-methyl-1-propyllithium,3-(t-butyldimethylsilylthio)-2,2-dimethyl-1-propyllithium,4-(t-butyldimethylsilylthio)-1-butyllithium,6-(t-butyldimethylsilylthio)-1-hexyllithium,3-(trimethylsilylthio)-2,2-dimethyl-1-propyllithium,3-(1,1-dimethylethylthio)-1-propyllithium,3-(1,1-dimethylethylthio)-2-methyl-1-propyllithium,3-(1,1-dimethylethylthio)-2,2-dimethyl-1-propyllithium,4-(1,1-dimethylethylthio)-1-butyllithium,5-(1,1-dimethylethylthio)-1-pentyllithium,6-(1,1-dimethylethylthio)-1-hexyllithium;8-(1,1-dimethylethylthio)-1-octyllithium,3-(1,1-dimethylpropylthio)-1-propyllithium,3-(1,1-dimethylpropylthio)-2-methyl-1-propyllithium,3-(1,1-dimethylpropylthio)-2,2-dimethyl-1-propyllithium,4-(1,1-dimethylpropylthio)-1-butyllithium,5-(1,1-dimethylpropylthio)-1-pentyllithium,6-(1,1-dimethylpropylthio)-1-hexyllithium, and8-(1,1-dimethylpropylthio)-1-octyllithium and their more hydrocarbonsoluble conjugated alkadiene, alkenylsubstituted aromatic hydrocarbon,and mixtures thereof, chain extended oligomeric analogs (n=1-5).

Non-polar compounds are preferably polymerized in a non-polar solventsuch as a hydrocarbon (as described above), since anionic polymerizationin the presence of such non-polar solvents is known to produce polyeneswith high 1,4-contents from 1,3-dienes. Polar solvents (modifiers) canbe added to the polymerization reaction to alter the microstructure ofthe resulting polymer, i.e., increase the proportion of 1,2 (vinyl)microstructure or to promote functionalization or randomization. Theamount of the polar modifier added depends on the vinyl content desired,the nature of the monomer, the temperature of the polymerization, andthe identity of the polar modifier. For polar monomers, preferredpolymerization solvents are polar solvents, although a hydrocarbon, ormixtures of polar and hydrocarbon solvents can also be used.

The polymers of Formulas (I) or (II) can optionally be hydrogenated,either before or after deprotection. Suitable hydrogenation techniquesare described in U.S. Pat. Nos. 4,970,254, 5,166,277, 5,393,843 and5,496,898, the entire disclosure of each of which is incorporated byreference. The hydrogenation of the functionalized polymer is conductedin situ, or in a suitable solvent, such as hexane, cyclohexane orheptane. This solution is contacted with hydrogen gas in the presence ofa catalyst, such as a nickel catalyst. The hydrogenation is typicallyperformed at temperatures from 25° C. to 150° C., with a archetypalhydrogen pressure of 15 psig to 1000 psig. The progress of thishydrogenation can be monitored by InfraRed (IR) spectroscopy or NuclearMagnetic Resonance (NMR) spectroscopy. The hydrogenation reaction isconducted until at least 90% of the aliphatic unsaturation has beensaturated. The hydrogenated functional polymer is then recovered byconventional procedures, such as removal of the catalyst with aqueousacid wash, followed by solvent removal or precipitation of the polymer.

Functionalized polymers of Formulas (I) or (II) can be further reactedwith other comonomers, such as di or polyesters, di- orpolyiisocyanates, di-, poly-, or cyclic amides, di- and polycarboxylicacids, and di- and polyols. For example, a protected functional polymercan be treated using the acid catalysts as described above in thepresence of a suitable comonomer to simultaneously deprotect thefunctional polymer and polymerize the functional end(s) thereof toproduce novel segmented block polymers. Alternatively, deprotectingconditions can be selected so as to copolymerize one functional endthereof with a suitable comonomer while maintaining the integrity of theother protecting group to provide a functional block copolymer. Stillanother alternative is to remove the protecting group of the functionalpolymer of Formulas (I) or (II) and to polymerize a functional blockcopolymer of the preceding sentence with the same or other comonomers toproduce novel segmented block polymers.

Still further, as noted above, multi-branched or star-shaped polymerswith protected functional groups, or their optionally hydrogenatedanalogues, can also be deprotected in accordance with the process of theinvention. Star polymers can be produced using the functional initiators(III) described above (singly or combinations-thereof), which, bydesign, incorporate the versatility of functional branch ends in thestar polymers. For example, hydroxy-, thio-, or amino-terminatedfunctional branches can be copolymerized with comonomers, such asorganic diacids (such as carboxylic acids), diisocyanates, and the like.The copolymers can also include non-functional branches in the polymer.This can provide improved impact resistance in molecules resulting fromfurther copolymerization of the star-shaped polymers with otherfunctional comonomers, for example, resultant polyester and/or polyamidemolecules.

Novel multi-branched or star-shaped polymers having functional ends canbe produced by polymerizing alkenylsubstituted aromatic hydrocarbons,conjugated dienes, and polar compounds, singly, sequentially, or asmixtures thereof, as described above, with protected functionalorganolithium initiators of Formula (III) (singly or as combinationsthereof to provide arms having different protecting groups and/ordifferent functional groups), and subsequently reacting the resultingcopolymer with multifunctional linking agents. This can lead to polymeranion chain lengths of approximately the same size.

Examples of useful linking or coupling agents useful for hydrocarbonmonomers include halosilanes, such as silicon tetrachloride and methyltrichlorosilane; halostannanes, such as tin tetrachloride; phosphorushalides, such as phosphorus trichloride; and isomeric (mixtures ofortho, meta and para) dialkenylaryls and isomeric di- and trivinylaryls,such as 1,2-divinylbenzene, 1,3-divinylbenzene, 1,4-divinylbenzene,1,2,4-trivinylbenzenes, 1,3-divinylnaphthalenes, 1,8-divinylnaphthalene,1,2-diisopropenylbenzene, 1,3-diisopropenylbenzene,1,4-diisopropenylbenzene, 1,3,5-trivinylnaphthalene, and other suitablematerials known in the art to be useful for coupling polymers, as wellas mixtures of coupling agents. See also U.S. Pat. Nos. 3,639,517 and5,489,649, and R. P. Zelinski et al in J.Polym.Sci., A3, 93, (1965) forthese and additional coupling agents. This linking process is described,for example, in U.S. Pat. No. 4,409,357 and by L. J. Fetters inMacromolecules, 9,732 (1976). Useful linking agents for polar monomersinclude, without limitation, reactive halogen compounds, such asα,α′-dibromo-p-xylene and α,α′,α″-tribromo-mesitylene, multifunctionalacrylates, such as ethylene glycol dimethylacrylate and glyceroltrimethacrylate, and the like. Mixtures of coupling agents can also beused. Generally, the amount of coupling agent used is such that themolar ratio of protected living polymer anions to coupling agents rangesfrom 1:1 to 24:1.

Nonfunctional initiators (such as n-butyllithium, sec-butyllithium, andtert-butyllithium) may also be mixed with the functional initiators ofFormula (III) to provide non-functional branch ends as well, which canserve to modify the physical properties of these star-shaped orradiating polymers, especially after their further copolymerization withother functional monomers, such as organic diacids or organicdiisocyanates.

Alternatively, novel multi-branched or star-shaped polymers possessingfunctional ends which may be the same or different, and/or bothfunctional and non-functional ends, may be produced by separatelypolymerizing alkenylsubstituted aromatic hydrocarbons, conjugateddienes, or polar monomers, as described above, with protected functionalinitiators (III) and/or with non-functional organolithium initiators,subsequently mixing the resulting separately produced anions, treatingthe resulting mixture with multifunctional linking agents, andoptionally hydrogenating before or after optionally deprotecting thefunctional ends of the polymer. This alternative method allows forcontrol of the molecular weight of the arms of the star polymer (forexample, different polymer anion chain lengths can be produced) andprovides for a more selective control of the physical properties of theresultant polymers.

The protecting groups can be removed from the ends of the arms of thestar polymer, prior to or after optional hydrogenation of the residualunsaturation of the arms, using the techniques described above. Thisincludes selective deprotection when different protecting groups arepresent, as detailed above. The star polymers thus formed may havehydroxyl, thio, and/or amino functional branch ends.

Molecular weights of the resulting linked or coupled polymers can varydepending on the molecular weight of the polymer anion and the number ofpotential functional linking groups on a coupling agent. The sizes ofthe branches of the linked polymer can be the same or vary.

Additionally, the process of the invention is useful for deprotecting awide variety of symmetrically or asymmetrically functional polymersproduced by reacting the living polymers described above with variousfunctionalizing agents. For example, addition of carbon dioxide (seeJ.Polym.Sci., Polym.Chem. 30, 2349 (1992)) to a living polymer having aprotected hydroxyl group would produce a polymer with one protectedhydroxyl and one carboxyl group, or the living polymer may be reactedwith 1,5 diazabicyclo-(3.1.0) hexane as described in U.S. Pat. No.4,753,991 to produce a polymer with one protected hydroxyl and one aminogroup. A polymer with one protected hydroxyl group and one protectedamino group can be prepared by reaction of the living anion with aprotected amino propyl bromide, see Macromolecules, 23, 939 (1990).Reaction of the living polymer anion with oxetane or substitutedoxetanes (see U.S. Pat. No. 5,391,637) would afford a polymer whichcontained one protected hydroxyl and a hydroxyl group. A polymer withtwo protected hydroxyl groups can be prepared by reaction of the livinganion with a silicon derived acetal, see U.S. Pat. No. 5,478,899.

Other polymers which can be deprotected in accordance with the presentinvention include asymmetrically substituted monofunctional polymershaving epoxy or isocyanate groups at one end, for example, by reactingthe lithium salt of the living polymers described above having aprotected hydroxyl group (before hydrolysis), with epichlorohydrin or byreacting the lithium salt itself with an equivalent of a diisocyanate,such as methylene 4,4-diphenyl diisocyanate (2/1 NCO/OH). Theseunsymmetrically substituted functional polymers could then be furtherreacted with other comonomers either with or without simultaneousdeprotection as described below.

Protected dihydroxy polymers alone and in their hydrogenated forms couldbe used as base materials to lend flexibility and higher impact strengthin a number of formulas to produce coatings, sealants, binders and blockcopolymers with polyesters, polyamides and polycarbonates as describedin UK Patent Application GB2270317A and in “Polytail” data sheets andbrochures (Mitsubishi Kasei America).

In the presence of acidic catalysts used to promote the formation ofmany of these block copolymer resins, the protecting group of thehydrogenated polymer is removed as well, allowing the exposed hydroxylgrouping in the base polymer molecule to simultaneously participate inthe block copolymer reaction.

For example, hydrogenated polymers may be reacted with bisphenol A andphosgene in the presence of appropriate catalysts with simultaneousdeprotection to yield a polycarbonate alternating block copolymer. Theresulting products are useful as molding resins, for example, to prepareinterior components for automobiles.

A segmented polyamide-hydrogenated block copolymer is also useful as amolding composition to prepare exterior automotive components and can beprepared, for example, by reacting hydrogenated polymers withcaprolactam or adipic acid and a diamine in the presence of a suitablecatalyst.

A segmented polyester-hydrogenated block copolymer can be produced byreaction of hydrogenated polymers with dimethyl terephthalate and a dioland a suitable acidic catalyst. Again, the products are useful asmolding compounds for exterior automotive components.

Isocyanate-terminated prepolymers can be produced from hydrogenatedpolymers by reaction with suitable diisocyanates (2/1 NCO/OH) as aboveand which can be further reacted with diols and additional diisocyanatesto form segmented polyurethanes useful for water based, low VOCcoatings. Inclusion of acid functional diols, such asdimethylolpropionic acid, in the polyurethane introduces pendantcarboxyl groups which can be neutralized with tertiary amines to affordwater dispersable polyolefin/polyurethane segmented polymers, useful forwater based coatings. This same principle could be applied to acrylicpolymers made with tertiary amine functional monomers included, whichcould be made by free radical polymerization following reacting thehydroxyl groups at the terminal ends of the polymer with acryloylchloride or methacryloyl chloride. Segmented polyurethane prepolymersmay be mixed with tackifying resins and used as a moisture-curablesealant, caulk or coating.

Another possible application in coatings would be the use of newdendrimers, based on the use of the polymer with hydroxyl functionalityat the termini thereof to form the core for dendritic hybridmacromolecules based on condensation or addition polymerizations,utilizing the hydroxyl functionality as the initiating site (see, forexample Gitsov and Frechet, American Chemical Society PMSE Preprints,Volume 73, August 1995).

Yet another application includes use as toughening polymers for epoxycomposites, utilizing the polymer core with the hydroxyl groupsconverted to half esters by reaction with anhydrides. These epoxyreactive polymers can then be utilized as reactants with epoxy resinsand amines in composite systems. Reacting the hydroxyl functionalpolymers into unsaturated polyesters provides a new polymer tougheningsystem for polyester molding compounds for automotive and other uses.For a review of the use of linear polymers for toughening of epoxies andpolyesters, see “Rubber-Toughened Plastics”, Edited By C.Keith Riew, ACSAdvances in Chemistry Series, #222.

Cathodic electrodepositabie coatings may be prepared from epoxyfunctional polymers described above by reacting with epoxy resins in thepresence of excess amine or polyamine, to completely react all the epoxygroups, distilling off excess amine, and neutralizing the resultingepoxy-amine adduct with water soluble organic or inorganic acids to formwater soluble, quaternary ammonium containing polymer salts (see forreference, U.S. Pat. Nos. 3,617,458, 3,619,398, 3,682,814, 3,891,527,3,947,348, and 4,093,594). Alternatively, the above epoxy-amine polymeradducts may be converted to quaternary phosphonium or sulfonium ioncontaining polymers, as described in U.S. Pat. No. 3,935,087.

An acrylate-terminated prepolymer curable by free-radical processes canbe prepared from a protected hydroxy, hydrogenated polymer by reactionwith a diisocyanate (2NCO/OH) followed by further reaction withhydroxyethyl acrylate in the presence of a basic reagent.

Another likely application for functionally terminated polymers includeuse as viscosity index (V.I.) improvers. Using carboxyl functionalmonomers, such as acrylic acid and methacrylic acid, and/or aminefunctional monomers such as acrylamide, along with free radicalinitiators in further polymerizations, can result in the formation ofpolymer segments at the periphery of each termini with amine or otherfunctionalities which, in addition to the advantageous properties of thepolymers as V.I. improvers, combines the ability to add functionality tothe polymers for dispersant properties (see, for example, U.S. Pat. Nos.5,496,898, 4,575,530, 4,486,573, 5,290,874, 5,290,868, 4,426,374, and5,272,211).

The versatility of the hydroxyl functional polymers of this invention,and the wide range of different segmented polymers (polyethers,polyesters, polyamides, polycarbonates, polyurethanes, etc.) which canbe initiated at the hydroxyl groups, leads to numerous possibleapplications as compatibilizers for polymer blends and alloys. Inaddition to the use of such blends for new applications, much recentinterest is generated in the use of compatibilizers to facilitatepolymer waste recycling.

The polar functional groups on the polymer chain ends allow the polymersof this invention to alter the surface properties of polymers likepolyethylene (including high density polyethylene, low densitypolyethylene, and linear low density polyethylene), polypropylene,polyisobutylene and copolymers and blends thereof. When the polymers ofthis invention are blended with non-polar polyolefins, the polarfunctional groups on the chain ends, being incompatible with thenon-polar polyolefin, will phase separate and migrate to the surface ofthe polyolefin. The polymers of the invention can be added to thepolyolefin in amounts from 1 to 25% by weight based on the weight of thepolyolefin. Properties such as surface adhesion are thus greatlyenhanced, leading to improved adhesion of pigments in printing inks forlabels, composite layering, and other adhesive applications. Analternative approach to modification of polymer surfaces to alterproperties by introduction of functional groups has been the use ofchemical reagents such as alkyllithiums (see, for example, A. J. Dias,K-W Lee, and T. J. McCarthy, Rubber & Plastics News, 18-20, Oct. 31,1988, and A. J. Dias and T. J. McCarthy, Macromolecules, 20, 1437(1987)).

Alternatively, protecting groups may be removed, either before or afteroptional hydrogenation of the aliphatic unsaturation, then thefunctional terminated polymer may be reacted with functional comonomersto produce novel copolymers using these and other processes. Thus, forexample, a hydroxy terminated polymer may be hydrogenated, and thenreacted with ethylene oxide in the presence of potassium tert-butoxideto produce a poly(ethylene oxide)-hydrogenated block copolymer. Thisreaction sequence affords a hydrogel.

Alternatively, the protected functional polymer may be reacted withfunctional comonomers, without simultaneously removing the protectinggroup. These copolymers then may be deprotected and then further reactedwith the same or different comonomers to form yet other novelcopolymers. Thus, for example, a hydroxyterminated polymer may behydrogenated, and then reacted with ethylene oxide in the presence ofpotassium tert-butoxide to produce a poly(ethylene oxide)-hydrogenatedcopolymer with one protected hydroxyl group on the polymer segment. Thisprotected hydroxyl can then be deprotected and a poly(ethylene oxide)polymer having different chain lengths grown onto both ends of thepolymer.

In another possible application, a living polymer may be reacted with analkenylarylhalosilane, such as styrenyldimethylchlorosilane, to yieldthe corresponding omega-styrenyl terminated macromonomer according tothe teachings of U.S. Pat. No. 5,278,244, which may then be furtherpolymerized by a variety of techniques to yield “comb” polymers which,on deprotection and hydrogenation yield branched polymers with, forexample, hydroxyfunctionality on the branch-ends. Suchmulti-functionality can be utilized to graft a water-soluble polymersuch as polyethylene oxide onto a hydrophobic polyolefinic core toproduce hydrogels.

In still another possible application, hydrogenated hydroxyterminatedbranches of the polymers may be further reacted with acryloyl chlorideor methacryloyl chloride, and the resultant acrylate ormethacrylate-terminated polymer further polymerized with monomersselected from the group of alkyl acrylates, alkyl methacrylates, anddialkylacrylamides to produce hydrogels. Further, acrylate ormethacrylate-terminated polymers may be polymerized by free-radicalprocesses.

The present invention will be further illustrated by the followingnon-limiting examples.

EXAMPLE 1 Deprotection of Tert-Butoxy Group from Polybutadiene withAmberlyst® 15 and Heat

Polybutadiene polymer having a tert-butoxy end group (0.5 g, 1.515×10⁻⁴mole) and Amberlyst®15 ion exchange resin (0.025 g, Aldrich) were heatedunder nitrogen from 20-200° C. at a heating rate of 10° C./min. A Hi-ResThermogravimetric Analyzer 2950 and Thermal Analyst 2000 (TAInstruments) were used to monitor the weight loss resulting from theelimination of isobutylene from the base polymer. Complete deprotection(loss of tert-butoxy signal) was determined by ¹H NMR analysis of theresulting polymer residue. Base polymer MW (GPC) before deprotection:M_(n)=3300; M_(w)=3500; M_(w)/M_(n)=1.07.

EXAMPLE 2 Deprotection of Tert-Butoxy Group from Polybutadiene withAmberlyst® 15 and Heat

Polybutadiene with a tert-butoxy protecting group (0.5 g, 1.515×10⁻⁴mole) and Amberlyst® 15 ion exchange resin (0.025 g, Aldrich) wereheated under nitrogen at 150° C. for 20 min. A Hi-Res ThermogravimetricAnalyzer 2950 and Thermal Analyst 2000 (TA Instruments) were used tomonitor the weight loss resulting from the elimination of isobutylenefrom the base polymer. Complete deprotection (loss of tert-butoxysignal) was determined by ¹H NMR analysis of the resulting polymerresidue. Base polymer MW (GPC) before deprotection: M_(n)=3300;M_(w)=3500; M_(w)/M_(n)=1.07.

EXAMPLE 3 Deprotection of Tert-Butoxy Group from Polybutadiene withAmberlyst® 15 in Refluxing Cyclohexane

Polybutadiene with a tert-butoxy protecting group (1.5 g, 3.448×10⁻⁴mole) and Amberlyst® 15 ion exchange resin (1.5 g, ground powder,Aldrich) were combined in cyclohexane (10 ml). The mixture was heated toreflux for 6 hours and monitored by thin layer chromatography (TLC). Theproduct solution was filtered to remove the Amberlyst® 15 resin. Thepolymer was precipitated in methanol. The solvent was evaporated underreduced pressure to give hydroxy-terminated polybutadiene. Completedeprotection was determined by ¹H NMR analysis (loss of tert-butoxysignal). Base polymer MW (GPC) before deprotection: M_(n)=4350;M_(w)=4700; M_(w)/M_(n)=1.09; 1,4-microstructure 87%.

EXAMPLE 4 Deprotection of Tert-Amyloxy Group from Polybutadiene withAmberlyst® 15 in Refluxing Cyclohexane

Polybutadiene with a tert-amyloxy protecting group (1.5 g, 3.125×10⁻⁴mole) and Amberlyst® 15 ion exchange resin (1.5 g, ground powder,Aldrich) were combined in cyclohexane (10 ml). The mixture was heated toreflux for 15 hours and monitored by thin layer chromatography (TLC).The product solution was filtered to remove the Amberlyst® 15 resin. Thepolymer was precipitated in methanol. The solvent was evaporated underreduced pressure to give hydroxy-terminated polybutadiene. Completedeprotection was determined by ¹H NMR analysis (loss of tert-amyloxysignal). Base polymer MW (GPC) before deprotection: M_(n)=4800;M_(w)=5100; M_(w)/M_(n)=1.07; 1,4-microstructure 86%.

EXAMPLE 5 Deprotection of Tert-Butoxy Group from Polybutadiene withAmberlyst® 15 in Refluxing Tert-Butylbenzene

Polybutadiene with a tert-butoxy protecting group (1.5 g, 3.448×10⁻⁴mole) and Amberlyst® 15 ion exchange resin (1.5 g, ground powder,Aldrich) were combined in tert-butylbenzene (10 ml). The mixture washeated to 170° C. for 5 hours and monitored by thin layer chromatography(TLC). The product solution was filtered to remove the Amberlyst® 15resin. The polymer was precipitated in methanol. The solvent wasevaporated under reduced pressure to give hydroxy-terminatedpolybutadiene. Complete deprotection was determined by ¹H NMR analysis(loss of tert-butoxy signal). Base polymer MW (GPC) before deprotection:M_(n)=4350; M_(w)=4700; M_(w)/M_(n)=1.09; 1,4-microstructure 87%.

EXAMPLE 6 Deprotection of Tert-Butoxy Group from Polyisoprene withAmberlyst® 15 in Refluxing Cyclohexane

Polyisoprene with a tert-butoxy protecting group (1.5 g, 2.121×10⁻⁴mole) and Amberlyst® 15 ion exchange resin (1.5 g, ground powder,Aldrich) were combined in cyclohexane (10 ml). The mixture was heated toreflux for 6 hours and monitored by thin layer chromatography (TLC). Theproduct solution was filtered to remove the Amberlyst® 15 resin. Thepolymer was precipitated in methanol. The solvent was evaporated underreduced pressure to give hydroxy-terminated polyisoprene. Completedeprotection was determined by ¹H NMR analysis (loss of tert-butoxysignal). Base polymer MW (GPC) before deprotection: M_(n)=6910;M_(w)=7370; M_(w)/M_(n)=1.08.

EXAMPLE 7 Deprotection of Tert-Amyloxy Group from Polyisoprene withAmberlyst® 15 in Refluxing Cyclohexane

Polyisoprene polymer with a tert-amyloxy protecting group (1.5 g,2.021×10⁻⁴ mole) and Amberlyst® 15 ion exchange resin (1.5 g, groundpowder, Aldrich) were combined in cyclohexane (10 ml). The mixture washeated to reflux for 12 hours and monitored by thin layer chromatography(TLC). The product solution was filtered to remove the Amberlyst® 15resin. The polymer was precipitated in methanol. The solvent wasevaporated under reduced pressure to give hydroxy-terminatedpolyisoprene. Complete deprotection was determined by ¹H NMR analysis(loss of tert-amyloxy signal). Base polymer MW (GPC) beforedeprotection: M_(n)=7420; M_(w)=7940; M_(w)/M_(n)=1.07.

EXAMPLE 8 Deprotection of Tert-Butoxy Group from Polystyrene withAmberlyst® 15 in Refluxing Tert-Butylbenzene

Polystyrene with a tert-butoxy protecting group (1.5 g, 3.658×10⁻⁴ mole)and Amberlyst® 15 ion exchange resin (1.5 g, ground powder, Aldrich)were combined in tert-butylbenzene (10 ml). The mixture was heated toreflux for 2 hours and monitored by thin layer chromatography (TLC). Theproduct solution was filtered to remove the Amberlyst® 15 resin. Thepolymer was precipitated in methanol. The solvent was evaporated underreduced pressure to give hydroxy-terminated polystyrene. Completedeprotection was determined by ¹H NMR analysis (loss of tert-butoxysignal). Base polymer MW (GPC) before deprotection: M_(n)=4100;M_(w)/M_(n)=1.17.

EXAMPLE 9 Deprotection of Tert-Butoxy Group from Polystyrene withAmberlyst® in Refluxing Cyclohexane

Polystyrene with a tert-butoxy protecting group (1.5 g, 1.875×10⁻⁴ mole)and Amberlyst® 15 ion exchange resin (1.5 g, ground powder, Aldrich)were combined in cyclohexane (10 ml). The mixture was heated to refluxfor 6 hours and monitored by thin layer chromatography (TLC). Theproduct solution was filtered to remove the Amberlyst® 15 resin. Thepolymer was precipitated in methanol. The solvent was evaporated underreduced pressure to give hydroxy-terminated polystyrene. Completedeprotection was determined by ¹H NMR analysis (loss of tert-butoxysignal). Base polymer MW (GPC) before deprotection: M_(n)=8000;M_(w)=10000; M_(w)/M_(n)=1.27.

EXAMPLE 10 Deprotection of Tert-Butoxy Group from Telechelic HydroxyFunctionalized Polybutadiene with Amberlyst® in Refluxing Cyclohexane

A telechelic hydroxy functionalized polybutadiene polymer with atert-butoxy protecting group at one functional end thereof (1.5 g,3.448×10⁻⁴ mole) and Amberlyst® 15 ion exchange resin (1.5 g, groundpowder, Aldrich) were combined in cyclohexane (10 ml). The mixture washeated to reflux for 12 hours and monitored by thin layer chromatography(TLC). The product solution was filtered to remove the Amberlyst® 15resin. The polymer was precipitated in methanol. The solvent wasevaporated under reduced pressure to give di-hydroxy-terminatedpolybutadiene. Complete deprotection was determined by ¹H NMR analysis(loss of tert-butoxy signal). Base polymer MW (GPC) before deprotection:M_(n)=4350; M_(w)=4700; M_(w)/M_(n)=1.09.

EXAMPLE 11 Selective Deprotection of Protected Telechelic Polybutadienewith Amberlyst® 15 and Heat

A telechelic dihydroxy polybutadiene polymer having a tert-butoxyprotecting group and a tert-butyl dimethylsilyl protecting group (0.5 g)and Amberlyst® 15 ion exchange resin (0.025 g, Aldrich) were heatedunder nitrogen at 150° C. for 40 min. A Hi-Res ThermogravimetricAnalyzer 2950 and Thermal Analyst 2000 (TA Instruments) were used tomonitor the weight loss resulting from the elimination of isobutylenefrom the base polymer. Deprotection of the tert-butoxy group wasdetermined by ¹H NMR analysis (loss of the tert-butoxy signal) of theresulting polymer residue. The tert-butyl dimethylsilyl protecting groupremained intact on the polymer.

EXAMPLE 12 Selective Deprotection of Polybutadiene Polymer Mixture withAqueous Acid in Refluxing Tetrahydrofuran

A 1:1 mixture of tert-butoxy protected polybutadiene (0.001 mole) andtert-butyldimethylsilyloxy protected polybutadiene (0.001 mole) wasprepared by physical mixing using a mechanical stirrer. The mixture wasdissolved in tetrahydrofuran (10 ml). Aqueous hydrochloric acid (1 ml,0.5 N, 2.5 equivalents) was added. The solution was heated to reflux for12 hours. The polymer was precipitated in methanol. The solvent wasevaporated under reduced pressure. ¹H NMR analysis of the residueindicated deprotection of the tert-butyldimethylsilyloxy group while thetert-butoxy group remained intact on the polymer. Tert-butoxy basepolymer MW before deprotection: M_(n)=4200; M_(w)=4600;M_(w)/M_(n)=1.08. Tert-butyldimethylsilyloxy base polymer MW beforedeprotection: M_(n)=3350; M_(w)/M_(n)=1.08.

EXAMPLE 13 Complete Deprotection of Polybutadiene Polymer Mixture withAmberlyst® 15 in Refluxing Tert-Butylbenzene

A 1:1 mixture (3 g) of tert-butoxy protected polybutadiene andtert-butyldimethylsilyloxy protected polybutadiene was prepared byphysical mixing using a mechanical stirrer. The mixture was placed intert-butylbenzene (30 ml) and Amberlyst® 15 ion exchange resin (3 g,ground powder, Aldrich) was added. The mixture was heated to reflux for15 hours and monitored by thin layer chromatography (TLC). The productsolution was filtered to remove the Amberlyst® 15 resin. The polymer wasprecipitated in methanol. The solvent was evaporated under reducedpressure. ¹H NMR analysis of the residue indicated complete deprotectionof both the tert-butyldimethylsilyloxy group and the tert-butoxy group.Tert-butoxy base polymer MW before deprotection: M_(n)=4200; M_(w)=4600;M_(w)/M_(n)=1.08. Tert-butyldimethylsilyloxy base polymer MW beforedeprotection: M_(n)=3350; M_(w)/M_(n)=1.08.

EXAMPLE 14 Deprotection of Tert-Butoxy Group from 4-Arm StarPolybutadiene Polymer with Amberlyst® 15 in Refluxing Cyclohexane

A polybutadiene star polymer with a tert-butoxy protecting group (3 g)and Amberlyst® 15 ion exchange resin (0.5 g, ground powder, Aldrich)were combined in cyclohexane (20 ml). The mixture was heated to refluxfor 20 hours and monitored by thin layer chromatography (TLC). Theproduct solution was filtered to remove the Amberlyst® 15 resin. Thepolymer was precipitated in methanol. The solvent was evaporated underreduced pressure to give hydroxy-terminated polybutadiene star polymer.Complete deprotection was determined by ¹H NMR analysis (loss oftert-butoxy signal).

EXAMPLE 15 Deprotection of Tert-Butoxy Group from Polymethylmethacrylate(PMMA) Star with Trimethylsilyl Iodide

A polymethylmethacrylate (PMMA) star polymer with a tert-butoxyprotecting group (0.5 g) was placed in chloroform (25 ml, distilled).Trimethylsilyl iodide (0.45 ml, three-fold molar excess relative totert-butoxy protecting groups) was added. The reaction was stirred atroom temperature for 1 hour. The solution was extracted with aqueoussodium bicarbonate solution three times to remove excess tert-butyliodide. The polymer was precipitated in methanol and then washed withexcess methanol. The solvent was evaporated under reduced pressure togive hydroxy-terminated polymethylmethacrylate star polymer. Completedeprotection was determined by ¹H NMR analysis (loss of tert-butoxysignal).

EXAMPLE 16 Deprotection of Tert-Butoxy Group from Polymethylmethacrylate(PMMA) Star with Amberlyst® 15 in Refluxing Tert-Butylbenzene

A PMMA star with a tert-butoxy protecting group (0.3 g) was placed intert-butylbenzene (10 ml). Amberlyst® 15 ion exchange resin (0.3 g,ground powder, Aldrich) was added to the solution. The mixture washeated to reflux (170° C.) for 1 hour. The product solution was filteredto remove the Amberlyst® 15 resin. The product filtrate was successivelywashed with THF. The solvent was evaporated under reduced pressure togive hydroxy-terminated polymethylmethacrylate star polymer. Completedeprotection was determined by ¹H NMR analysis (loss of tert-butoxysignal).

EXAMPLE 17 Deprotection of Tert-Butoxy Group from Polylutadiene withTrimethylsilyl Iodide

A polybutadiene polymer with a tert-butoxy protecting group (1.5 g) isplaced in carbon tetrachloride (15 ml). Trimethylsilyl iodide (0.1 ml)is added. The reaction is stirred at room temperature and monitored bythin layer chromatography (TLC) until complete. Methanol (1 ml) andaqueous HCl (1 ml, 0.5 N solution) are added to destroy excesstrimethylsilyl iodide and hydrolyze the intermediate trimethylsilylethers formed during the reaction. The volatiles are removed on therotary evaporator and the residue is taken up in diethyl ether. Theether solution is washed with aqueous sodium bisulfite, aqueous sodiumbicarbonate, and brine. The solvent is evaporated under reduced pressureto give hydroxy-terminated polybutadiene. The extent of deprotection isdetermined by ¹H NMR analysis (loss of tert-butoxy signal).

EXAMPLE 18 Deprotection of Tert-Butoxy Group from Polybutadiene withAqueous Acid in Refluxing Toluene/Dioxane

A polybutadiene polymer with a tert-butoxy protecting group (1.5 g) isplaced in aqueous hydrochloric acid (1 ml, 0.5 N), toluene (10 ml), anddioxane (10 ml). The solution is heated to reflux and monitored by thinlayer chromatography (TLC) until complete. The polymer is precipitatedin methanol. The solvent is removed under reduced pressure. The extentof deprotection is determined by ¹H NMR analysis (loss of tert-butoxysignal).

EXAMPLE 19 Deprotection of Protected Telechelic Polybutadiene withAqueous Tetrabutylammonium Fluoride/Tetrahydrofuran

A telechelic polybutadiene polymer with a tert-butoxy and tert-butyldimethylsilyloxy protecting groups (1.5 g), tetrabutylammonium fluoride(0.5 g), and water (10 ml) are combined in tetrahydrofuran (15 ml). Themixture is stirred at ambient temperature and monitored by thin layerchromatography (TLC) until complete. The polymer is precipitated inmethanol. The solvent is removed under reduced pressure. The extent ofdeprotection (loss of tert-butyl dimethylsilyloxy signal) is determinedby ¹H NMR analysis.

EXAMPLE 20 Deprotection of Protected Telechelic Polybutadiene withAqueous Acid in Refluxing Dioxane/Toluene

A telechelic polybutadiene polymer with a tert-butoxy and tert-butyldimethylsilyloxy protecting groups (1.5 g), aqueous hydrochloric acid (1ml, 0.5 N), dioxane (10 ml), and toluene (10 ml) are heated to refluxand monitored by thin layer chromatography (TLC) until complete. Thepolymer is precipitated in methanol. The solvent is removed underreduced pressure. The extent of deprotection (loss of tert-butyldimethylsilyloxy signal) is determined by ¹H NMR analysis.

EXAMPLE 21 Deprotection of Tert-butoxy Group of Polybutadiene with2-Toluenesulfonic Acid

Polybutadiene having a tert-butoxy protecting group (1 gram) was heatedin cyclohexane (20 ml) with 0.3 grams p-toluenesulfonic acid. Thereaction was allowed to continue for 1 hour under reflux conditions.After cooling to room temperature, the reaction mixture was washed withdistilled water, followed by washing with brine. The organic layer wasseparated using a separatory funnel and dried with sodium sulfate. Afterfiltering the sodium sulfate, the solvent was evaporated using a RotaryEvaporator and the final product was dried under high vacuum. Completedeprotection (loss of tert-butoxy signal) was determined by ¹H NMRanalysis of the resulting polymer residue. The final product isα-hydroxy polybutadiene. Base polymer MW (GPC) before deprotection:M_(n)=4400 g/mol; M_(w)=4900; M_(w)/M_(n)=1.09.

EXAMPLE 22 Deprotection of Tert-butoxy Group of Polybutadiene withFerric Chloride and Acetic Anhydride

Deprotection of polybutadiene having a tert-butoxy protecting group wascarried out by esterification followed by hydrolysis. Polybutadienehaving a tert-butoxy protecting group (0.5 gram) in anhydrous ether (2ml), acetic anhydride (0.58 g), and anhydrous ferric chloride (FeCl₃)(0.092 g) were stirred at room temperature for 15 hours. A saturatedaqueous sodium bicarbonate solution (10 ml) was added, and the mixturewas stirred for 3 hours. The aqueous layer was extracted twice withether (30 ml), and the organic layer was separated using a separatoryfunnel, then dried with sodium sulfate. After filtering the sodiumsulfate, the solvent was evaporated using a Rotary Evaporator, and thefinal product was dried under high vacuum. Complete deprotection (lossof tert-butoxy signal) was determined by ¹H NMR analysis of theresulting polymer residue. The final product is α-hydroxy polybutadiene.Base polymer MW (GPC) before deprotection: M_(n)=4400 g/mol; M_(w)=4900;M_(w)/M_(n)=1.09.

EXAMPLE 23 Deprotection of Tert-butoxy Group of Polybutadiene withTrifluoroacetic Acid (TFAA)

Polybutadiene having a tert-butoxy protecting group (1.0 gram) incyclohexane (10 ml) and trifluoroacetic acid (CF₃COOH) (10 ml) werestirred at room temperature for 15 hours. A saturated aqueous sodiumbicarbonate solution was added, and the mixture was washed withdistilled water. The final product was dried under high vacuum. Partialdeprotection (loss of tert-butoxy signal) was determined by ¹H NMRanalysis of the resulting polymer residue.

EXAMPLE 24 Deprotection of Tert-butoxy Group of Polybutadiene withTrimethylsilyl Iodide (TMSI)

Polybutadiene having a tert-butoxy protecting group (1.1 gram) incyclohexane (11 ml) and trimethylsilyl iodide (0.356 g) were stirred at50° C. for 4 hours. Methanol (2 ml) was added to the reaction mixture,and the reaction mixture was washed with sodium bisulfite, sodiumbicarbonate and brine. The final product was dried under high vacuum.Partial deprotection (loss of tert-butoxy signal) was determined by ¹HNMR analysis of the resulting polymer residue.

The foregoing examples are illustrative of the present invention and arenot to be construed as limiting thereof. The invention is defined by thefollowing claims, with equivalents of the claims to be included therein.

That which is claimed is:
 1. A process for removing protecting groupsfrom polymers, comprising treating a polymer having at least twodissimilar protecting groups, one of said protecting groups having theformula —[A(R¹R²R¹)] in which A is carbon and R¹, R², and R³ are eachindependently selected from the group consisting of hydrogen, alkyl,substituted alkyl groups containing lower alkyl, lower alkylthio, andlower dialkylamino groups, aryl or substituted aryl groups containinglower alkyl, lower alkylthio, and lower dialkylamino groups, andcycloalkyl and substituted cycloalkyl containing 5 to 12 carbon atoms,in the presence of an acid catalyst capable of removing at least one ofsaid dissimilar protecting groups without removing other dissimilarprotecting groups, said acid catalyst comprising a compound selectedfrom the group consisting of organic acids selected from the groupconsisting of para-toluenesulfonic acid, trifluoroacetic acid, aceticacid, and methanesulfonic acid, mineral acids selected from the groupconsisting of hydrochloric acid, phosphoric acid and sulfuric acid;heterogeneous acid systems selected from the group consisting of acidion exchange resins and acid clays; Lewis acids selected from the groupconsisting of trimethylsilyl iodide, iron (III) chloride with aceticanhydride, and boron trihalides; and fluoride ion sources selected fromthe group consisting of tetraalkylammonium fluoride, potassium fluoride,sodium fluoride, cesium fluoride, lithium fluoride, lithiumtetrafluoroborate, hydrogen fluoride, and pyridine hydrogen fluoridecomplex.
 2. The process of claim 1, wherein said polymer is amulti-branched or star polymer of the formulaL[(Q)_(d)—R_(n)—Z—J-[A(R¹R²R³)]_(x)]_(m) wherein: Q is a saturated orunsaturated hydrocarbyl group derived by incorporation of a compoundselected from group consisting of conjugated diene hydrocarbons,alkenylsubstituted aromatic hydrocarbons, polar compounds selected fromthe group consisting of esters, amides and nitrites of acrylic andmethacrylic acid, and mixtures thereof; d is an integer from 10 to 2000;R is a saturated or unsaturated hydrocarbyl group derived byincorporation of a compound selected from the group consisting ofconjugated diene hydrocarbons, alkenylsubstituted aromatic hydrocarbons,and mixtures thereof; n is an integer from 0 to 5; Z is a branched orstraight chain hydrocarbon group which contains 3-25 carbon atoms,optionally containing aryl or substituted aryl groups; J is oxygen,sulfur, and nitrogen; and [A(R¹R²R³)]_(x) is a protecting group, inwhich A is an element selected from Group IVa of the Periodic Table ofElements; R¹, R², and R³ are each independently selected from the groupconsisting of hydrogen, alkyl, substituted alkyl groups containing loweralkyl, lower alkylthio, and lower dialkylamino groups, aryl orsubstituted aryl groups containing lower alkyl, lower alkylthio, andlower dialkylamino groups, and cycloalkyl and substituted cycloalkylcontaining 5 to 12 carbon atoms; and x is dependent on the valence of Jand varies from one when J is oxygen or sulfur to two when J isnitrogen; L is a linking or coupling agent; and m is an integer from 3to 50, said polymer having at least two different protecting groups—[A(R¹R²R³)]_(x).
 3. The process of claim 1, wherein said polymer is apolymer of Formula (I) FG-(Q)_(d)—R_(n)—Z—J-[A(R¹R²R³)]_(x)  (I)wherein: FG is a protected functional group; Q is a saturated orunsaturated hydrocarbyl group derived by incorporation of a compoundselected from group consisting of conjugated diene hydrocarbons,alkenylsubstituted aromatic hydrocarbons, polar compounds selected fromthe group, consisting of esters, amides and nitrites of acrylic andmethacrylic acid, and mixtures thereof; d is an integer from 10 to 2000;R is a saturated or unsaturated hydrocarbyl group derived byincorporation of a compound selected from the group consisting ofconjugated diene hydrocarbons, alkenylsubstituted aromatic hydrocarbons,and mixtures thereof; n is an integer from 0 to 5; Z is a branched orstraight chain hydrocarbon group which contains 3-25 carbon atoms,optionally containing aryl or substituted aryl groups; J is oxygen,sulfur, or nitrogen; and [A(R¹R²R³)]_(x) is a protecting groupdissimilar from FG, in which A is an element selected from Group IVa ofthe Periodic Table of Elements; R¹, R², and R³ are each independentlyselected from the group consisting of hydrogen, alkyl, substituted alkylgroups containing lower alkyl, lower alkylthio, and lower dialkylaminogroups, aryl or substituted aryl groups containing lower alkyl, loweralkylthio, and lower dialkylamino groups, and cycloalkyl and substitutedcycloalkyl containing 5 to 12 carbon atoms; and x is dependent on thevalence of J and varies from one when J is oxygen or sulfur to two whenJ is nitrogen.
 4. The process of claim 3, wherein the organic acid isselected from the group consisting of para-toluenesulfonic acid,trifluoroacetic acid, acetic acid, and methanesulfonic acid.
 5. Theprocess of claim 3, wherein the mineral acid is selected from the groupconsisting of hydrochloric acid, phosphoric acid, and sulfonic acid. 6.The process of claim 3, wherein the heterogeneous acid system isselected from the group consisting of acid ion exchange resins and acidclays.
 7. The process of claim 3, wherein the Lewis Acid is selectedfrom the group consisting of trimethylsilyl iodide, iron (III) chloridewith acetic anhydride, and boron trihalides.
 8. The process of claim 3,wherein the fluoride ion source is selected from the group consisting oftetraalkylammonium fluoride, potassium fluoride, sodium fluoride, cesiumfluoride, lithium fluoride, lithium tetrafluoroborate, hydrogenfluoride, and pyridine hydrogen fluoride complex.
 9. The process ofclaim 3, wherein said treating step is conducted at a temperaturebetween about 20° C. and about 200° C.
 10. The process of claim 3,wherein said treating step comprises treating a mixture of the polymerand a hydrocarbon solvent, polar solvent, excess acid catalyst or amixture thereof.
 11. The process of claim 10, wherein said treating stepcomprises heating the mixture at the reflux temperature thereof.
 12. Theprocess of claim 3, wherein: the polymer of Formula (I) comprises atleast one tertiary-butyldimethylsilyl protecting group and at least onetertiary alkyl protecting group; and said treating step comprisestreating the polymer of Formula (I) in the presence of acid catalystunder conditions to selectively remove one of said tertiary alkylprotecting group and said tertiary-butyldimethylsilyl protecting groupwithout removing the other.
 13. The process of claim 12, wherein saidtreating step comprises heating the polymer in the presence of aheterogeneous acid system to selectively remove the tertiary alkylprotecting group without removing the tertiary-butyldimethylsilylprotecting groups.
 14. The process of claim 12, wherein said treatingstep comprises heating the polymer in the presence ofpara-toluenesulfonic acid to selectively remove the tertiary alkylprotecting group without removing the tertiary-butyldimethylsilylprotecting group.
 15. The process of claim 12, wherein said treatingstep comprises heating the polymer in the presence of hydrochloric acidto selectively remove the tertiary-butyldimethylsilyl protecting groupwithout removing the tertiary alkyl protecting group.
 16. The process ofclaim 1, wherein said polymer is a multi-branched or star polymerproduced by polymerizing a monomer selected from the group consisting ofconjugated diene hydrocarbons, alkenylsubstituted aromatic hydrocarbons,and polar monomers selected from the group consisting of esters, amidesand nitrites of acrylic and methacrylic acid, singly, sequentially or asa mixture thereof, with a protected functional organometallic initiatorof the formula M—R_(n)—Z—J-[A(R¹R²R³)]_(x)  (III) wherein: M is analkali metal; R is a saturated or unsaturated hydrocarbyl group derivedby incorporation of a compound selected from the group consisting ofconjugated diene hydrocarbons, alkenylsubstituted aromatic hydrocarbons,and mixtures thereof; n is an integer from 0 to 5; Z is a branched orstraight chain hydrocarbon group which contains 3-25 carbon atoms,optionally containing aryl or substituted aryl groups; J is oxygen,sulfur, or nitrogen; [A(R¹R²R³)]_(x) is a protecting group, in which Ais an element selected from Group IVa of the Periodic Table of Elements;R¹, R², and R³ are independently selected from hydrogen, alkyl,substituted alkyl groups containing lower alkyl, lower alkylthio, andlower dialkylamino groups, aryl or substituted aryl groups containinglower alkyl, lower alkylthio, and lower dialkylamino groups, andcycloalkyl and substituted cycloalkyl containing 5 to 12 carbon atoms;and x is dependent on the valence of J and varies from one when J isoxygen or sulfur to two when J is nitrogen, to form a mono-protected,mono-functionalized living polymer; and coupling said living polymerwith at least one other living polymer with a linking agent to provide amulti-branched or star polymer, said polymer having at least twodifferent protecting groups —[A(R¹R²R³)]_(x).
 17. The process of claim16, wherein the organic acid is selected from the group consisting ofpara-toluenesulfonic acid, trifluoroacetic acid, acetic acid, andmethanesulfonic acid.
 18. The process of claim 16, wherein the mineralacid is selected from the group consisting of hydrochloric acid,phosphoric acid and sulfonic acid.
 19. The process of claim 16, whereinthe heterogeneous acid system is selected from the group consisting ofacid ion exchange resins and acid clays.
 20. The process of claim 16,wherein the Lewis Acid is selected from the group consisting oftrimethylsilyl iodide, iron (III) chloride with acetic anhydride, andboron trihalides.
 21. The process of claim 16, wherein the fluoride ionsource is selected from the group consisting of tetraalkylammoniumfluoride, potassium fluoride, sodium fluoride, cesium fluoride, lithiumfluoride, lithium tetrafluoroborate, hydrogen fluoride, and pyridinehydrogen fluoride complex.
 22. The process of claim 16, wherein saidtreating step is conducted at a temperature between about 20° C. andabout 200° C.
 23. The process of claim 16, wherein said treating stepcomprises treating a mixture of the polymer and a hydrocarbon solvent,polar solvent, excess acid catalyst, or a mixture thereof.
 24. Theprocess of claim 16, wherein said treating step comprises heating themixture at the reflux temperature thereof.
 25. The process of claim 16,wherein: the polymer includes different protecting groups prepared bypolymerizing a monomer selected from the group consisting of conjugateddiene hydrocarbons, alkenylsubstituted aromatic hydrocarbons, and polarmonomers, singly, sequentially or as a mixture thereof, with protectedfunctional organolithium initiators of Formula (III) in which[A(R¹R²R³)]_(x) is different.